Polish Coffee Cake (with Almonds)

Base:

1. Preheat the oven to 175 degrees Celsius/ 350 degrees Fahrenheit. Grease a springform 26 cm/ 10.2 inches and sprinkle it with some flour. Shake to spread the flour all over the form and pat the form on the bottom to remove the excess flour. Do this over the sink.
2. Carefully roast the ground almonds, without adding any fat, for a couple of minutes. Keep an eye on the pan and stir often, the almonds will burn easily if unattended. Transfer immediately to a plate and let cool while you mix the batter.
3. Mix the soft butter and sugar until light and creamy.
4. Add the eggs, one at a time, mixing well in between.
5. Mix the flour and the baking powder together and sieve them over the egg mixture.
6. Add the roasted almonds and incorporate.
7. Pour the batter into the prepared springform and bake in the preheated oven for about 40 minutes or until a toothpick inserted in the middle comes out clean. Leave the cake in the pan for about 5-10 minutes, then transfer it to a wire rack and let it cool completely.
8. You can bake the cake one day in advance, let it cool, wrap in cling film and fill it the next day.
9. In the meantime roast the slivered almonds, stirring often and keeping an eye on them. They should be golden brown. Immediately transfer to a plate and let cool.

Coffee buttercream:

1. Brew the coffee. Place the ground coffee into a cup and pour the boiling water over it. Allow to infuse while you prepare the rest. Make another small cup of regular coffee, you will need a few tablespoons for soaking the cake base. Drink the rest.
2. Place the sugar and the water into a small heavy bottom saucepan. Heat until the sugar dissolves and the mixture starts to simmer and then let simmer for 3 minutes. Careful not to burn yourself with the sugar.
3. Place the egg yolks into a mixing bowl. Slowly pour the sugar syrup into the mixture while mixing all the time until the mixture thickens.
4. Cream the butter until light and fluffy. Slowly add the sugar-egg mixture while mixing all the time.
5. Sieve the thick coffee over the bowl. Discard the coffee rests. Mix well.
6. Slice the cake once. Place one slice on a serving platter. Soak it with 3 or 4 tablespoons of the regular coffee.
7. Spread half of the buttercream on the first slice and top with the second slice. Spread the rest of the buttercream on top and sprinkle the roasted slivered almonds all over the top of the cake.

Optional:

1. Beat the heavy cream shortly. Add icing sugar and unsweetened cocoa powder and continue beating until stiff.
2. Spread the whipped cream on the sides of the cake and sprinkle with chocolate sprinkles.